Photographic emulsions containing trinuclear iminol cyanine dyes



Patented Sept. 1948 PHOTOGRAPHIC EMULSIONS CONTAINING TRINUCLEAR IMINOL CYANIN'E DYES Alfred W. Anish, Vestal, N. Y., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing.

Original application January 19,

1945, Serial No. 573,631. Divided and this application March 14, 1945, Serial No. 582,819

4 Claims.

This invention relates to sensitizing, filter, and anti-halation dyes for photographic materials, and particularly to trinuclear iminol cyanlne dyes as sensitlzers.

Cyanine dyes containing more than two nuclei are already known. Dyes oi this category are illustrated, for example, in United States Patent 2,276,554, and in British Patent 489,335. It will be noted that in the dyes referred to in these patents the nucleus appearing in the dye, in addition to the two terminal nitrogenous heterocyclic nuclei, is heterocyclic in character and of the type known as rhodanine nucleus. In these dyes, however, the central heterocyclic nucleus serves to supply the terminals of two distinct resonating systems.

I have now discovered a new class of trinuclear iminol cyanine dyes in which two heterocyclic nitrogenous nuclei are linked by a monomethine radical, and in which the third heterocyclic nitrogenous nucleus, though joined to the monomethine chain: contributes a terminal common to a shared resonating systeminvolving the other two nuclei. These new dyestuffs have certain significant properties which are not possessed by the known dyestuffs. For instance, the dyes are not only excellent sensitizers for silver-halide emulsions, but also form stable silver salts with silver ions. These properties not only make the dyes valuable as sensitizing dyes, but also as fllter and anti-halaticn dyes for silver-halide emulsions.

The primary object of the present invention is to provide a new class of trinuclear iminol cyanines as sensitizing dyes for photographic materials.

Other objects and advantages of this invention will be apparent by reference to the following specification in which its preferred details and embodiments are described.

I have found that when a methylene bis-azole is condensed with a five-membered or six-membered heterocyclic ring'system, in the presence of a basic condensing agent, trinuclear iminol cyanine dyes are formed which are not only excellent sensitizers for photographic emulsions, but are also excellent filter and anti-halation dyes for photographic emulsions.

The trinuclear iminol cyanine dyes prepared according to the present invention are characterized by the following general formula:

wherein X and Y are the same or different and represent the atoms necessary to complete a heterocyclic ring system of the type usual in cyanine dyes, e. g., substituted or unsubstituted indoienines, iepidines, oxaaoles, oxazolines, selenazoles, selenazollnes. pyridine, quinoline, thiazoles, thiazolines; diazoles and quinazolines and the corresponding substituted or unsubstituted polycyclic compounds such as benzthiazoles, benrselenazoles, naphthothiazoles, naphthoselenazoles, diazines and the like, Z represents the atoms necessary to complete a five-membered or six-membered heterocyclic nucleus, e. g., a substituted or unsubstituted barbituric acid, thicbarbituric acid, rhodanine, oxazoledione, thiazclone, pyrazolone, imidazolone, imidazoledione and the like, n represents a positive odd integer not greater than live, and R is either hydrogen or a heavy metal, e. g., silver, lead, mercury and the like.

The process of preparing the above trinuclear iminol cyanines comprises heating on a steam bath or under reflux conditions an alcoholic solution of a methylene bis-azole with a fivemembered or six-membered heterocyclic intermediate derived from barbituric acid, thio-barbituric acid, rhodanine, hydantoin (imidazolone) thiohydantoin (imidazoledione), oxazoledione, thiazolone or pyrazoione having a reactive acetanilido group linked to a ring carbon atom next wherein Z and n have the same values as indicated above under the general formula. More particularly, the compounds represented by this general formula are as follows: 4-(Y-acetanilidm allylidene) -l benzothiazo1yl-3 methyl--pyrazclone, 4 (Y-acetanilidoallylider1e)-Z:i-rnethyl-1- phenyl-S-pyrazolone, 5 acetanilidomethylene-B- allylrhodanine, 5-acetanilidopropadienylidene-B- allylrhodanine, 5 acetanilidoniethylene-S-phenylrhodanine, 5-acetanilidomethylene-S-ethylrhodanine, 5 acetanilidomethylene 3-ethy1-2-tlrio 2,4 (3,5) oxazoledione, 5-(' -acetanilidoallylidene) 2 diphenylam-inc-4 (5) -thiazolone, 5-( acetanilidoallylidene)-3-ethyl-2-thio-2, 4 (3,5)- oxazoledione, 5 (v-acetanllidoallylidene) -3-eth-' yl-l-phenyl-2-thiohydantoin, 5 (5-acetanilidoo -pentadienylidene) -3-ethylrhodanine.

As condensing agents employed in the preparation of the new dyes of the present invention, the following may be employed: hterocyclic nitrogenous bases such as pyridine, dimethyl pyridine, ethyl pyridine, etl'iylmethyl pyridine, trimethyl pyridine, quinoline and the like, using basic catalysts, such as triethyl amine, tributyl amine, sodium or potassium carbonate, or acid condensing agents such as acetic acid or acetic anhydride. In general, the amount of condensing agent used may vary within wide limits, e. g., from 1 to 25 mols. Concentrations ranging from 1 mol to about 15 mols are preferred.

When 1 moi of a methylene bis-azole is condensed with 1 mol of a five or six-rnembered heterocyclic intermediate in the presence or a condensing agent, for instance pyridine, a reaction occurs which may be written as follows:

The following examples describe in detail the methods for accomplishing the above objects, but

. 4 it is to be understood that they are inserted merely for the purpose of illustrations and are not be construed as limiting the scope of the invention.

EXAMPLE I 2-diphenylamino-4-hydrory-5 -[a,a-dibenzothiazolyl-butadienyl (1,3) l-thiazoline i 6 it E -N (CuHs):

2.8 grams (1 mol) of methylene bis-benzthiazole and 4.4 grams (1 mol) of 5-( -acetanilidoa1- lylidene) -2-diphenylamino-4 (5) -thiazolone were mixed in 20 cc. of dry pyridine containing 1 cc. of triethylamine. The mixture was boiled under reflux for 1 hours, cooled and then diluted with 5 cc. of water. The mixture was stirred vigorously for a few minutes and then further diluted with 10 cc. of water. On standing an oil separated out which was segregated from the supernatant liquid by decantation. The oil was dissolved in a minimum amount of methanol and diluted with 5% perchloric acid solution. The dye which sepa rated was boiled out twice with ethyl alcohol and then dried.

EXAMPLE II 2-thio-3-ethyl-4-hydroxy-5- [6,6-dibenz0thiazolyl-butadienyl (1,3) l -dihydro1razole 2.8 grains (1 mol) of methylene bis-benzthiazole and 3.3 grams (1 mol) of 5-( -acetanilidoal1y'lidene) -3-ethyl-2-thio-2,4 (3,5) -oxazoledione were mixed with 20 cc. of dry pyridine containing 1 cc. of triethylamine. The mixture was boiled under reflux for 1 hours, cooled and then diluted with 5 cc. of water. The mixture was stirred vigorously for a few minutes and then further diluted with 10 cc. of water. On standing an oil separated out which was segregated from the supernatant liquid by decantation. The oil was dissolved in a minimum amount of methanol and diluted with 5% perchloric acid solution. The dye which separated was boiled out twice with 95% ethyl alcohol and then dried.

Exsurrs I11 i-phenyl-Z-thio-S-ethyl- 4- hydroccy- 5 [at-dibenzoxazolyl-butadienyl (1,3) l-dihydrimidazole 5 perchloric acid solution. The dye which separated Was boiled out twice with 95% ethyl alcohol and then dried.

EXAMPLE IV 1 -phenyl-3-methyl-5-hydroscy-4- ta-benzoxazolyl-a-benzothiaaolyl-butadienyl (1,3) l-pyrazole o-c-o n N/ i \N 2.6 grams (1 mol) of 2-benzoxazolyl-2-benzothiazolyl-methane and 3.4 grams (1 mol) of 4-(- -acetanilidoallylidene) 3- methyl-l-phenylfi-pyrazolone were mixed with 20 'cc. of dry quinoline containing 1 cc. of triethylamine. The mixture was boiled under reflux for 1 hours, cooled and then diluted with 5 cc. of water. The mixture was stirred vigorously for a few minutes and then further diluted with cc. of water. On standing an oil separated out which was segregated from the supernatant liquid by decantation. The oil was dissolved in a minimum amount of methanol and diluted with 5% perchloric acid solution. The dye which separated was boiled out twice with 95% ethyl alcohol and then dried.

minutes and then further diluted EXAMPLE V 2-thi0-3-ethyl-4-hydromy-5-[6,8-dibe1i2oihiazolyl-hexatrienyl (1,3,5) l-dihydrothiazole in in 2.8 grams (1 mol) of methylene bis-benzthiazole and 3.6 grams (1 mol) of 5-(e-acetanilido-A pentadienylidene) -3-ethylrhodanine were mixed in 20 cc. of dry ethyl pyridine containing 1 cc. of tributylamine. The mixture was boiled under reflux for 1 hours, cooled and then diluted with 5 cc. of water. The mixture was stirred vigorously for a few minutes and then further diluted with 10 cc. of water. On standing an oil separated out which was segregated from the supernatant liquid by decantation. The oil was dissolved in a minimum amount of methanol and diluted with 5% perchloric acid solution. The dye which separated was boiled out twice with ethyl alcohol and then dried.

EXAMPLE VI 2-thio-3-allyl-4-hydroxy-5-(;B,fl-dibenzthiazolylethenyl) -dihydr0thiazole Bro-t 1.4 grams of methylene bis-benzthiazole and 1.6 grams of 3-allyl-5-acetanilidomethylene rhodanine were dissolved in 15 cc. of dry pyridine containing 1 cc. of triethylamine. The mixture was refluxed for 1 hours, cooled and then diluted with 5 cc. of water. The mixture was stirred vigorously and then further diluted with 10 cc. of water. The oil which separated soon thickened and the liquid portion was decanted. The oil was dissolved in a minimum amount of methanol and diluted liberally with a 5% perchloric acid solution. The dye which separated was boiled out twice with ethyl aldohol.

An ethyl alcohol solution of 20 mg. of the dye was incorporated in l kilogram of silver chloride emulsion containing a small amount of silver bromide and having a total content of 4-5% silverhalide. The dye imparts a sensitivityto about 650 mp, with a maximum sensitivity at about 600 m 7 EXAMPLE VII 2-thio-3-allyl 4-hydroxy-5- (p,p-dibenzoxazolylethenz/l) -dihydrothiazole 6.4 grams water added to precipitate the dye as an oil. cooled mixture The dye imparts a sensitivity to about 630 me, with a maximum sensitivity at about 570 m EXAMPLE VIII 2-thio-3-alZyZ-4-hydromy 5 (B-benzorazolyl-fibenzothz'azolyl-ethenyl) -dihydrothiazole Hail Al -S used as the starting materials.

An ethyl alcohol solution of 20 mg. of the dye was incorporated in l kilogram of silver chloride Exmrm IX 2-thio-3-allyl-4-hydroxy-5- [6,6- dibenzothiazolylbutadzenyl (1,3) l-dihydrothiazole N/Fm 4 grams of 3-allyl-E-acetanilidopropadienyl- 3. 1,3- hodanine, and 3.2 grams of separated was boiled alcohol.

The about 620 m1, about 570 m dye imparts a sensitivity to with a maximum sensitivity at EXAMPLE X G-hydroacy 2,4 dilceto 5-[a,a-dibenzothiazolylbutadienyl (1,3) l-tetrahydropyrimidz'ne EXAMPLE XI Z-thzo- 4 -lceto 6 hydroxy-S- la-benzowazolyl-abenzothiazolyl butadz'enyl (1,3)] tctTahg/dropyrimidine 2.7 grams (1 mol) of 2-benzoxazolyl-2'-benzothiazolyl methane and 2.9 grams (1 mol) of 5- (v-acetanilidoallylidene) -2-thio-4,6 diketohexahydropyrimidine were mixed with cc. of dry pyridine containing 1.0 cc. of triethylamine. The mixture was boiled under reflux for 1 /2 hours,

cooled and then diluted with 5 cc. of water. The

mixture was stirred vigorously for a few minutes and then further diluted with 10 cc. of water. On standing an oil separated out which was segregated from the supernatant liquid by decantation, The oil was dissolved in a minimum amount of methanol and diluted with 5% perchloric acid these trinuclear iminol cyanine dyes, the dye L may be dissolved in methyl or ethyl alcohol and a volume of this solution containing from 5 to 50 milligrams of the dye added to a liter of emulsion. While in general practice it may not be necessary to add the dye in amounts larger than those above given, generally for satisfactory results, amounts usually ranging from 5 to milligrams are sufiicient to obtain the maximum sensitizing effect. However, I do not wish to limit my invention to the quantities just indicated, the most suitable amount will in each case be found by a few comparative experiments. The dyes may be added to the emulsion in the form of solutions. Suitable solvents as indicated in the examples are the alcohols, for instance, methyl or ethyl alcohol which may be anhydrous or diluted with a small volume of water. In actual practice, the dyes are applied to the emulsion during any stage of its production, however, they are preferably added to the finished emulsion before being cast.

The above examples are illustrative only, and should not .be construed as limiting the invention, since it will be aparent to those skilled in the art, that the dyes of the present invention may be incorporated into photographic emulsions by methods other than those described herein.

The dyes of this invention are further characterized by their ability to form insoluble heavy metal salts, e. g., silver, lead and mercury salts, due to the presence of a salt-forming hydroxyl group in the merocyanine nucleus. Thus, for example, in the presence of silver ions insoluble silver salts are formed. These silver salts, moreover, are soluble in photographic processing baths, such as sodium tl'iiosulfalte. Accordingly, the dyes of this invention are readilyappli-cable as nondlfiusing photographic filter and anti-halation dyes in photographic materials in the form of their silver salts. The dyes may be incorporated EXAMPLE XII A photographic filter layer was prepared by I mixing the following ingredients to form a colored silver salt dispersion in gelatin:

Solution A 2-thio-3-allyl-4-hydroxy-5 4 6,49 dibenzoxazolyl ethenyl) dihydrothiazole--- grams 2.7

Water cc Sodium carbonate (anhydrous) grams 2.1

Gelatin (10% solution) cc 25 Solution B Water cc 100 Silver nitrate "grams" 1.7

Solution 0 Gelatin (10% solution) cc 100 Solution B was added to Solution A with rapid stirring. After several minutes, Solution C was added. The silver of the silver nitrate formed a silver salt with the hydroxy group of the dye in the gelatin solution. The final gelatin suspension thus obtained was then coated on a photographic film in the customary manner to serve as a yellow filter layer for blue light absorption. The silver salt of the dye is non-diffusing.

The amount of silver salt used according to the present invention will vary somewhat, depending upon the color desired. In general, an amount more or less than that given in Example XII may be used for satisfactory results.

For the production of anti-h'alation coatings, the silver salts of the trinuclear imin-ol cyanine dyes of the present invention are incorporated into gelatin, treated with silver nitrate, and the dispersions thus obtained are cast in a known manner as coatings in the intermediate layer, between the support and the emulsion or as a backing layer on the rear surface of the emulsion support, or as an antl-halation layer on the emulsion, when the material is intended to be exposed through the support.

EXAMPLE XHI A photographic anti-[halation layer was prepared by mixing the following ingredients to form a colored silver salt dispersion in gelatin:

Solution A l -phenyl3-methyl-5-hydroxy-4- [fi-benzox azolyl-o-benzothiazolyl butadienyl (1,3) pyrazole grams 7 .0 Water cc 200 Sodium hydroxide (4%) cc 7.5 Gelatin (10% solution) cc- 100 Solution B Water -oc- 100 Silver nitrate rgrams 3.4

Solution 0 Gelatin (10 solution) cc 300 Solution B was added to Solution A with rapid stirring. After several minutes, Solution C was added. The final gelatin suspension of the silver 11 salt thus obtained was coated on a support in the customary manner as an anti-halatin layer.

The filter and anti-halo coatings prepared as described above have been found to have particularly good filter and anti-halation properties and to have no effect on the normal keeping properties of the light sensitive layer.

It will be understood that where in the claims appended hereto the term filter layer is used, that such is intended to include anti-halation layer.

This application is a division of my co-pending application Serial No. 573,631 filed on January 19, 1945, now abandoned.

While the present invention has been described in considerable detail with reference to certain preferred procedures, materials and uses, it is understood that the new class of trinuclear iminol cyanine dyes and their use as sensitizing, filter and anti-halation dyes is not limited thereto, and that numerous variations and modifications described in the foregoing specification may be made as, for example, the dyes which contain a merocyanine nucleus, e.g., oxazoledione, hydantoin (imidazolone) and rhodanine nucleus, as illus trated in Examples 2, 3, and to 9 inclusive, may be further treated with a quaternizing compound such as methyl iodide. The quaternated compound is then condensed under reflux conditions with a cyclammonium base or salt such as N-methyl-Z-methylbenzthiazole having a reactive methyl group in the alpha position to the nitrogen.

atom in the presence of a condensing agent such as pyridine, quinoline and the like. In the first reaction (alkylation) the trinuclear iminol cyanine is modified to the extent that the nitrogen atom in the 3-position of the oxazoledione, hydantoin or rhodanine ring is quaternized and the sulfur atom in the 2-position is converted to a thioether group. In the second reaction (condensation), the alkylated trinuclear iminol cyanine condenses with a cyclammonium base or salt whereby new compounds, which are also useful as sensitizers, filter and anti-halation agents, having the following general formulae are obtained:

wherein R, X and Y and n have the same values as in the above general formula, R1 represents an alkyl, alkylene or aryl radical, R2 represents an alkyl, X represents an acid radical of the type usual in cyanine dyes and Q represents either nitrogen, oxygen or sulfur.

I claim:

1. A photographic light-sensitive element which comprises a support and a. gelatino silverhalide emulsion containing a sensitizing dye characterized by the following general formula:

wherein X and Y represent the atoms necessary to complete a nitrogenous heterocyclic ring system, Z represents the atoms necessary to complete a member selected from the class consisting of a five-menibered and six-membered heterocyclic ring system and n represents a positive odd integer of from one to five.

2. A photographic light-sensitive element which comprises a, support and a gelatino silverhalide emusion containing a sensitizing dye corresponding to the formula:

CaHo

3. A photographic light-sensitive element which comprises a support and a gelatino silverhalide emulsion containing a sensitizing dye corresponding to the formula:

4. A photographic light-sensitive element which comprises a support and a gelatino silverhalide emulsion containing a sensitizing dye corresponding to the formula:

min.

ALFRED W. ANISH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

